Improvement in wood-bending machines



UivrTnn STaTns FaTnNT EDWARD C. HARRIS, OF NEW YORK, N. Y.

Specification forming part of Letters Patent No. 525,944, dated February527, 1866.

To all whom it may concern:

Beit known that I, EDWARD C. Hnnnis, of No. 150 West Forty-Eighthstreet, in the city, county, and State of New York, have invented a newand useful Improvement in Bending Wood; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, which willenable others skilled in the art to make and use the same, referencebeing had to the accompanying drawings, forming part of thisspecification, in which- Figure l represents an elevation, partly insection, on the line y of Fig. 2, of an apparatus made according to myinvention. Fig. 2 shows a cross-section taken on the line x of Fig. l,Fig. 3,21. modiiicationof a portion of the apparatus.

Similar letters of reference indicate like parts.

This inven tion consists in bending wood to the shapes required-as, forinstance, the rims or cases for pianos, square or grand-by forcing thestuft' into concave beds, in contradistinction from the familiar methodof drawing it about convex forms. Itis also adapted for the applicationof veneers.

The invention further consists in the combination, with said concaveforms, of movable supplementary sections for bending parts whose curvesextend beyond the limit of one hundred and eighty degrees, ashereinafter explained.

In carrying out my invention I use metallic plates J, which can beeasily bent and afterward straightened out again to a flat state. Thewood H, to he bent, is placed between these plates, and may either beone piece, as in bending the solid piece for the inside of a piano-case,called the block,77 or it may be composed of several sheet-s or layersof wood for the case itself. In bending several layers, in order to makethe case of a piano, the usual veneer of ornamental wood is placed onthe outside of the layers and bent up with them. o

The mode usually followed in bending wood, whether a solid piece orseveral thin layers or veneers, is to steam the stuff to be bent so asto soften its Jbers, and then to bend it around a form. This mode is notuseful in bending the curved parts of piano-cases, because it isnecessary in making pianos that all the stuff be dry, it being common tokiln-dry it after it clamps.

is well seasoned. `Another objection to this i mode arises from theexpansion given to the stuff lengthwise when it is bent up around aconvex surface, thereby making it necessary to allow for this increaseof length when cutting the stuft' out. Moreover, this expansion is notuniform, and therefore it becomes difficult to iit the case to theadjacent parts.

My invention is intended to get rid of these difficulties and also toavoid the necessity, now universal, in making pianos with roundedcorners, as well the cycloid as square and grand pianos, of building upthe rounded portions piece by piece. The parts built up are required tobe strong, and therefore it is necessary to add greatly to their bulk.These parts are therefore cumbrous and their construction is expensive.A

In carrying out my invention I use a concave bed, into which the stufflto be bent is forced, and I apply my invention in bending the frontcorners and other parts which have sharp curves, as well as the partswhose curves are drawn with a considerable radius.

F designates any platform to which the bed E may be attached.

In Fig. l the vbed E is made in two parts hinged to the platform at a a,so as to be capable of being opened outward. When the sections ofthe bedare closed their inner ends, b b, meet on the line Gr, so that the innerface of the sections form a bed whose shape is to be of the shape to begiven to the stuff. 'To the upper ends of the sections of the bed Iattach, by strap-hinges I, supplementary secvtions C C, whose innerfaces when the supplementary sections are closed are cont-inuations ofthe curves of the bed E.

The letters A designate blocks whose size and contour are such as toenable the workman to place them in the concavity of the bed, theirplace, however, being above the stuff to be bent.

The letters B B' designate clamps which serve to bend the stuif and tohold it after it is bent. Some of them are pivoted to the platform, someof them to the bed E, vand some of them are detachable from theapparatus. Their blocks (l are all detachable, being held by their endsin the sockets e of the These blocks extend across the al paratus, andhave most of them a screw-rod passing through them, whose ends workagainst metallicplates set in the block A or in the bed E, or on thesupplementary sections (j, as the case may be. The detachable rclamps Bhave their screws in their iixed sides cl.

The form given to the apparatus in Fig. l is intended to illustrate theinanner'of forming the entire outline of the case ofa cycloid piano. Inbending the stuft' for a piano of that kind 4it is desirable to form thefront corners at the same time withthe rest of the case; but since thecurved line thus produced is greater than a half circle it would not bepossible to remove the stuff from the bed after the operation of bendingunless it was removed laterally, even if the stuff was successfullydriven down into the bed. Besides this difculty it is desirable to holdthe ends of the stuff firmly during the operation. I have thereforeprovided the supplementary sections G C.

In using the apparatus shown in Fig. l the blocks d of the clamps andthe blocks A are removed and the supplementary sections G are thrownback. The sections of the bed E are then turned outward aboutone-quarter of a circle, which movement will bring their ends o b b c inabout the same horizontal line.

If the stu to be bent consists of layers or veneers their surfaces areto be coated with glue before they are placed together. The plates J areto be brought to a hat condition, and having been heated to a hightemperature the stnif is placed between the plates and the whole laidupon the bed, with which the lower plate will be in contact at thepoints c b b c. The middle 011e of the blocks, A, is next laid upon theupperplate, J, and pressureis brought to bear thereon sufliciently toenable the workman to secure said block within the clamps B. In order toeffect this the sections of the bed E are forced inward until theirinner ends, b b, are brought together, the construction of thosesections being such that a powerful leverage is obtained in forcing thestuff down into the concavity of the bed.

When that part of the stuff which comes down into the central part ofthe bed has been iirmly secured the Lipper side blocks, A, are broughtup against the plates J and the stut H, and pressure is brought to bearupon them by means of the horizontal clamp B, and those clamps B whichare pivoted to the sections of the bed E, and they are in this mannerforced snugly into the concavity of the bed. The supplementary sectionsO ot' the bed are then brought down to the position shown in Fig.

1,so as to bend the ends of the stu to form the corners and front partsof the case. Each of the said supplementary sections has a socket, 7c,to receive the end of a lever, D, by means of which' they are broughtdown to the required position, When the ends of the stuff H and theinclosing-plates will be bent over on the adjacent parts ot' the blocks,so as to form the corners of the piano-case and those portions of itsfront which are on either side of the space left for the bench ot' keys.Clamps B are next applied, so as to inclosethe plates and stuff betweenthe supplementary sections and the adjacent parts of the blocks A. Whenthe stuff has been held in this way for about aday it may safely beremoved from the apparatus.

It will be observed that the stuff is by this system bent without beingsaturated or softened by steam or liquid, and it has not therefore lostits character of dryness, and can be immediately used. Furthermore,great solidity is imparted to the corners of the case, which are made bymy mode as strong as the straighter parts ot the case withoutbeing builtup piece by piece, and without being made thicker than the other parts.By forcing the stuff into a concave bed in this way between.inclosing-plates whose surfaces are always at all points in contactwith the stuff I accomplish the bending without separating the bers andwithout permitting the stuff to become increased in length. Furthermore,by bending the ornamental with the body ofthe case I give to it the samefixed contour and unite them together in the same operation.

When the block or piece of solid wood which is pnt inside the case of apiano as a lining or support is to be bent it is necessary to confineits ends rigidly, so as to prevent the fracture of its bers, since itsexibility is not as great as is the mass of layers or veneers. In Fig. 3I have shown a manner of confining its endsin the operation of bendinginthe frame E. I do this by means of clamps L, whose screw-rods passthrough longitudinal slots in plates J J, and which hold the block H sotightly compressed between the plates as to prevent it from moving orexpanding while it is being forced down into its bed.

This method of bending wood can be applied to any form-as, forinstance,to the construction in one piece of the cases of gra-nd pianos. In thatcase the bed ofthe apparatus must be of a shape corresponding to theshape of the piano front or frame, and it may be necessary i to changethe places ot' the hinges ce, and to divide the bed E into a greaternumber of sections.

This invention is applicable also to all cabinet-work which has curvedlines or surfaces.

The apparatus may be of wood or metal, and is to be of suitable strengthand character, and guides may be placed on each side of the bed so as toprevent the plates J and wood and veneers H from lateral displacement,and to make them more in a vertical line.

'.lhe blocks A may be made of wood or metal. In bending thick solidstuif, such as pianoblocks, the blocks A are made hot, so as to heat thestuff more or less, and thereby cause its bers to become contracted onthat side which is to be most contracted in bending it to a concaveshape, while the bed itself, which is contiguous to the convex side ofthe stuif, is left comparatively cold, so that the bers will becontracted in a less degree; but in bending stuft` which consists of'thin layers glued together, and stuff on which veneers are laid to beglued and bent at the same time,botl1 sides oi' the stuff are inclosedbetween hot plates, and the Veneers and stuff or the several layers ofthe stuff' become properly and firmly eeniented at the same timethey arebent in shape.

I claim as new and desire to secure by Let ters Patentv l. Bending thefronts of pianos, Whether formed of thin sheets ot' wood glued togetherand veneered, as described,or in one piece and veneered, by forcing suchfront or block into specified.

EDWARD C. HARRIS.

Witnesses M. M. LIVINGSTON, S. H. WALES.

